You can turn off Excel's "File ... already exists" warning by setting the Application.DisplayAlerts VBA variable. Here is a short example:

    #!/usr/bin/perl -w


    use strict;
    use Cwd;
    use Win32::OLE;
    use Win32::OLE::Const 'Microsoft Excel';


    my $application = Win32::OLE->new("Excel.Application");
    my $workbook    = $application->Workbooks->Add;
    my $worksheet   = $workbook->Worksheets(1);

    $worksheet->Cells(1,1)->{Value} = "Hello World";

    # Get current directory using Cwd.pm
    my $dir = cwd();


    # Turn off some Excel warnings
    $application->{DisplayAlerts} = "False";

    $workbook->SaveAs($dir . '/win32ole.xls');

    # Turn them back on (just in case)
    $application->{DisplayAlerts} = "True";


    $workbook->Close;
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--
John.